Many modern powders- such as Hodgdon's "Extreme" powders, are temperature insensitive. The three I use most (and are universally popular as well)- Varget, H4350, and 8208 XBR are all in that class. One less variable to worry about...
Effects of temp and humidity on bullet flight are unnoticeable at "typical" zero ranges of 100 or 200 yards (with these types of powders). It's long-range where those variables come into play...
POI shift from barrel temp depends on the barrel- if high quality and stress-relieved, sporter contours can continue to shoot well even when hot.
It's more a function of barrel stiffness- than contour.
I had a 20" Savage factory lightweight sporter that did not suffer from POI shifts when hot. Short= stiffer, for length, than one of the same contour that's much longer.